Preparation and use of thallium palladate as cover layer of metal anodes

Abstract

Preparation and use of a new electrochemical active substance for the cover layer of metal anodes, which substance is thallium palladate and is obtained as a cardinal-red compound, which is cubic-face-centered, sufficiently characterized in pure crystalline form and, thus, constitutes a new electrochemical active substance for the cover layer of metal anodes.

What is claimed is: 
     
       1. Method of manufacturing thallium palladate (TlPd 3  O 4 ) as a cardinal-red cubic face centered compound in stoichiometric composition and pure crystalline form comprising heating of thallium nitrate (TlNO 3 ) to about 350° C to yield cubic Tl 2  O 3  and NO and NO 2 , heating Tl 2  O 3  to about 500° C to yield Tl 2  O 3  and O 2 , adding PdO, and effecting the reaction according to the equation   1/2 O.sub.2 + Tl.sub.2 O + 6 PdO → 2 TlPd.sub.3 O.sub.4.     
     
     
       2. Method of manufacturing thallium palladate (TlPd 3  O 4 ) as a cardinal-red cubic face centered compound in stoichiometric composition and pure crystalline form comprising mixing 1 Mol PdO and 4 to 5 Mol TlNO 3 , heating the mixture slowly to about 500° to 600° C, removing excess Tl 2  O 3  by sublimation at about 650° C and removing palladium by boiling with aqua regia. 
     
     
       3. The method of making TlPd 3  O 4  comprising the steps of effecting the reaction of Tl 2  O with PdO in the presence of oxygen at a temperature above about 500° C, and removing excess Tl 2  O 3  and palladium. 
     
     
       4. The method as defined in claim 3 wherein said Tl 2  O is obtained from heating Tl 2  O 3  at a temperature of about 500°-600° C. 
     
     
       5. The method as defined in claim 4 wherein said Tl 2  O 3  is obtained by heating TlNO 3  above about 300° C.